Handbook on sourdough biotechnology

Tai Lieu Chat Luong Handbook on Sourdough Biotechnology Marco Gobbetti • Michael Gänzle Editors Handbook on Sourdough Biotechnology Editors Marco Gobbetti Department of Soil, Plant and Food Science University of Bari Aldo Moro Bari, Italy Michael Gänzle Department of Agricultural, Food, and Nutritional Science University of Alberta Edmonton, Canada ISBN 978-1-4614-5424-3 ISBN 978-1-4614-5425-0 (eBook) DOI 10.1007/978-1-4614-5425-0 Springer New York Heidelberg Dordrecht London Library of Congress Control Number: 2012951618 © Springer Science+Business Media New York 2013 This work is subject to copyright All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed Exempted from this legal reservation are brief excerpts in connection with reviews or scholarly analysis or material supplied specifically for the purpose of being entered and executed on a computer system, for exclusive use by the purchaser of the work Duplication of this publication or parts thereof is permitted only under the provisions of the Copyright Law of the Publisher’s location, in its current version, and permission for use must always be obtained from Springer Permissions for use may be obtained through RightsLink at the Copyright Clearance Center Violations are liable to prosecution under the respective Copyright Law The use of general descriptive names, registered names, trademarks, service marks, etc in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use While the advice and information in this book are believed to be true and accurate at the date of publication, neither the authors nor the editors nor the publisher can accept any legal responsibility for any errors or omissions that may be made The publisher makes no warranty, express or implied, with respect to the material contained herein Printed on acid-free paper Springer is part of Springer Science+Business Media (www.springer.com) Contents History and Social Aspects of Sourdough Stefan Cappelle, Lacaze Guylaine, M Gänzle, and M Gobbetti Chemistry of Cereal Grains Peter Koehler and Herbert Wieser 11 Technology of Baked Goods Maria Ambrogina Pagani, Gabriella Bottega, and Manuela Mariotti 47 Technology of Sourdough Fermentation and Sourdough Applications Aldo Corsetti 85 Taxonomy and Biodiversity of Sourdough Yeasts and Lactic Acid Bacteria Geert Huys, Heide-Marie Daniel, and Luc De Vuyst 105 Physiology and Biochemistry of Sourdough Yeasts M Elisabetta Guerzoni, Diana I Serrazanetti, Pamela Vernocchi, and Andrea Gianotti 155 Physiology and Biochemistry of Lactic Acid Bacteria Michael Gänzle and Marco Gobbetti 183 Sourdough: A Tool to Improve Bread Structure Sandra Galle 217 Nutritional Aspects of Cereal Fermentation with Lactic Acid Bacteria and Yeast Kati Katina and Kaisa Poutanen 10 Sourdough and Gluten-Free Products Elke K Arendt and Alice V Moroni 229 245 v vi Contents 11 Sourdough and Cereal Beverages Jussi Loponen and Juhani Sibakov 265 12 Perspectives Michael Gänzle and Marco Gobbetti 279 Index 287 Chapter History and Social Aspects of Sourdough Stefan Cappelle, Lacaze Guylaine, M Gänzle, and M Gobbetti 1.1 Sourdough: The Ferment of Life The history of sourdough and related baked goods follows the entire arc of the development of human civilization, from the beginning of agriculture to the present Sourdough bread and other sourdough baked goods made from cereals are examples of foods that summarize different types of knowledge, from agricultural practices and technological processes through to cultural heritage Bread is closely linked to human subsistence and intimately connected to tradition, the practices of civil society and religion Christian prayer says “Give us this day our daily bread” and the Gospels report that Jesus, breaking bread at the Last Supper, gave it to the Apostles to eat, saying, “This is my body given as a sacrifice for you” Language also retains expressions that recall the close bond between life and bread: “to earn his bread” and “remove bread from his mouth” are just some of the most common idioms, not to mention the etymology of words in current use: “companion” is derived from cum panis, which means someone with whom you share your bread; “lord”, is derived from the Old English vocabulary hlaford, which translates as guardian of the bread [1] The symbolic assimilation between bread and life is not just a template that has its heritage in the collective unconscious, but it is probably a precipitate of the history of culture and traditions Throughout development of the human civilization, (sourdough) bread was preferred over unleavened cereal products, supporting S Cappelle (*) • L Guylaine Puratos Group, Industrialaan 25, Groot-Bijgaarden, Belgium e-mail: SCapelle@puratos.com M Gänzle Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Canada M Gobbetti Department of Soil, Plant and Food Science, University of Bari Aldo Moro, Bari, Italy M Gobbetti and M Gänzle (eds.), Handbook on Sourdough Biotechnology, DOI 10.1007/978-1-4614-5425-0_1, © Springer Science+Business Media New York 2013 S Cappelle et al the hypothesis of a precise symbolism between the idea of elaborate and stylish, and that of sourdough Fermentation and leavening makes bread something different from the raw cereals, i.e an artifact, in the sense of “made art” Besides symbolism, sourdough bread has acquired a central social position over time Bread, and especially sourdough bread, has become central in the diet of peasant societies This suggests that the rural population empirically perceived sensory and nutritional transformations, which are also implemented through sourdough fermentation In other words, the eating of bread, and especially of sourdough bread, was often a choice of civilization The oldest leavened and acidified bread is over 5,000 years old and was discovered in an excavation in Switzerland [2] The first documented production and consumption of sourdough bread can be traced back to the second millennium B.C [3] Egyptians discovered that a mixture of flour and water, left for a bit of time to ferment, increased in volume and, after baking along with other fresh dough, it produced soft and light breads Much later, microscopic observations of yeast as well as measurements of the acidity of bread from early Egypt demonstrate that the fermentation of bread dough involved yeasts and lactic acid bacteria – the leavening of dough with sourdough had been discovered [4] Eventually, the environmental contamination of dough was deliberately carried out by starting the fermentation with material from the previous fermentation process Egyptians also made use of the foam of beer for bread making At the same time, Egyptians also selected the best variety of wheat flour, adopted innovative tools for making bread, and used high-temperature ovens The Jewish people learned the art of baking in Egypt As the Bible says, the Jews fleeing Egypt took with them unleavened dough In Greece, bread was a food solely for consumption in wealthy homes Its preparation was reserved for women Only in a later period, does the literature mention evidence of bakers, perhaps meeting in corporations, which prepared the bread for retail sale The use of sourdough was adopted from Egypt about 800 B.C [4] Greek gastronomy had over 70 varieties of breads, including sweet and savoury types, those made with grains, and different preparation processes The Greeks used to make votive offerings with flour, cereal grains or toasted breads and cakes mixed with oil and wine For instance, during the rites dedicated to Dionysus, the god of fertility, but also of euphoria and unbridled passion, the priestesses offered large loaves of bread The step from the use of sacrificial bread to the use of curative bread was quick Patients, who visited temples dedicated to Asclepius (the god of medicine and healing), left breads, and, upon leaving the holy place, received a part of the breads back imbued with the healing power attributed to the god [5, 6] The use of sourdough is also part of the history of North America The use of sourdough as a leavening agent was essential whenever pioneers or gold prospectors left behind the infrastructure that would provide alternative means of dough leavening Examples include the Oregon Trail of 1848, the California gold rush of 1849, and the Klondike gold rush in the Yukon Territories, Canada, in 1898 During the 1849 gold rush, San Francisco was invaded by tens of thousands of men and women in the grip of gold fever Following the gold rush, sourdough bread remained an element that distinguishes the local tradition until today Some bakeries in San Francisco claim to use sourdough that has been propagated for over 150 years The predominant History and Social Aspects of Sourdough yeast in San Francisco sourdoughs is not brewer’s yeast but Kazachstania exigua (formerly Saccharomyces exiguus), which is tolerant to more acidic environments Lactobacillus sanfranciscensis (formerly Lactobacillus brevis subsp lindneri and sanfrancisco) was first described as a new species in San Francisco sourdough [7] The use of sourdough during the Klondike gold rush in 1898 resulted in the use of “sourdough” to designate inhabitants of Alaska and the Yukon Territories and is even in use today The Yukon definition of sourdough is “someone who has seen the Yukon River freeze and thaw”, i.e a long-term resident of the area From antiquity to most recent times, the mystery of leavening has also been unveiled from a scientific point of view The definitive explanation of microbial leavening was given in 1857 by Louis Pasteur The scientific research also verified an assumption that the Greeks had already advanced: sourdough bread has greater nutritional value Pliny the elder wrote that it gave strength to the body The history and social significance of the use of sourdough is further described below for countries such as France, Italy and Germany where this traditional biotechnology is widely used, and where its use is well documented 1.2 History and Social Aspects of Sourdough in France The history of sourdough usage in France was linked to socio-cultural and socioeconomic factors There is little information about sourdough usage and bakery industries (it seems to be more appropriated than baking), in general, in France before the eighteenth century It seems as if sourdough bread was introduced in Gaul by the Greeks living in Marseille in the fourth century B.C In 200 B.C., the Gauls removed water from the bread recipe and replaced it with cervoise, a drink based on fermented cereal comparable to beer They noticed that the cloudier the cervoise, the more the dough leavened Thus, they started to use the foam of cervoise to leaven the bread dough The bread obtained was particularly light During the Middle Ages (400–1400 A.D.), bread making did not progress much and remained a family activity In the cities, the profession of the baker appeared The history of bread making in France was mainly linked to Parisian bakers because of the geographic localization of Paris The regions with the biggest wheat production were near Paris, and Paris had major importance in terms of inhabitants In that period, the production of bread was exclusively carried out using sourdough fermentation, the only method known at that time Furthermore, the use of sourdough, thanks to its acidity, permitted baking without salt, an expensive and taxed (Gabelle) raw material, and allowed one to produce breads appropriate for eating habits in the Middle Ages [8] The seventeenth century marked a turning point in the history of French bakery Until then, sourdough was used alone to ensure fermentation of the dough even if in some French regions wine, vinegar or rennet was added Toward 1600 A.D., French bakers rediscovered the use of brewer’s yeast for bread making The yeast came from Picardie and Flanders in winter and from Paris breweries in summer The breads 12 Perspectives 283 for use of sourdough as a leavening agent Equipment for industrial sourdough fermentation is typically designed to carry out (semi-)automated batch fermentations according to the fermentation scheme of traditional procedures, and is thus incompatible with large-scale and continuous bread production [28] Consequently, sourdough fermentation is increasingly carried out by specialized suppliers to the baking industry [29] The use of sourdough in bakeries employs stabilized, usually dried, preparations that are shelf stable This second line of sourdough products in addition to traditional fermentations allows for product innovation to match the specialized need of individual customers Examples include ready-to-use, active sponge doughs, dried sourdough products enriched with exopolysaccharides or flavour compounds derived from the Maillard reaction, and starter cultures selected for specific metabolic traits for improved bread quality It is noteworthy that lyophilized starter cultures for direct inoculation of bread dough have not found widespread commercial use in baking applications, in contrast to the predominant use of starter cultures in meat and dairy fermentations Freeze-dried cultures fail to develop the required metabolic activity in straight dough processes, and thus require revitalization in a pre-ferment or sponge dough prior to use In-house propagation of sourdough with occasional restoration of the desired fermentation microbiota with cereal-based freeze-dried starter preparations is thus a preferred option for many bakeries The increasing use of sourdough as a baking improver also allows the inclusion of non-conventional organisms and raw materials Continuous propagation of sourdough invariably selects for fermentation microbiota consisting of lactic acid bacteria and yeasts The industrial production of baking improvers, however, can be started with other food-grade organisms that grow in cereal substrates and maintain dominance over one or a few stages of fermentations Bifidobacteria [30], propionibacteria [31], fungi and acetic acid bacteria [32] all grow in cereal substrates and have been employed in experimental cereal fermentations Moreover, traditional cereal fermentations employed in Africa, Asia, and Latin America for production of steamed bread, beverages, porridges, vinegar, or condiments provide a source of fermentation organisms that are highly adapted to cereal substrates The metabolic potential of these organisms vastly differs from sourdough lactic acid bacteria and their use allows novel functionalities for baked products References Vogel RF, Knorr R, Müller MRA, Steudel U, Gänzle MG, Ehrmann MA (1999) Non-dairy lactic fermentations: the cereal world Antonie van Leeuwenhoek 76:403–411 Meroth CB, Walter J, Hertel C, Brandt MJ, Hammes WP (2003) Monitoring the bacterial population dynamics in sourdough fermentation processes by using PCR- denaturing gradient gel electrophoresis Appl Environ Microbiol 69:475–482 De Vuyst L, Neysens P (2005) The sourdough microflora: biodiversity and metabolic interactions Trends Food Sci Technol 16:43–56 Minervini F, Lattanzi A, De Angelis M, Di Cagno R, Gobbetti M (2012) Artisan bakery or laboratory propagated sourdoughs: influence on the diversity of lactic acid bacterium and yeast microbiotas Appl Environ Microbiol doi:10.1128/AEM.00572-12 284 M Gänzle and M Gobbetti Ehrmann MA, Behr J, Böcker G, Vogel RF (2011) The genome of L sanfranciscensis after 18 years of continuous propagation In: Abstract, presented at the 10th symposium on lactic acid bacteria, Egmond aan Zee Accessed via www.lab10.org on 20 June 2012 Walter J (2008) Ecological role of lactobacilli in the gastrointestinal tract: implications for fundamental and biomedical research Appl Environ Microbiol 74:4985–4996 Frese SA, Benson AK, Tannock GW, Loach DM, Kim J, Zhang M, Oh PL, Heng NC, Patil PB, Juge N, Mackenzie DA, Pearson PM, Lapidus A, Dalin E, Tice H, Goltsman E, Land M, Hauser L, Ivanova N, Kyrpides NC, Walter J (2011) The evolution of host specialization in the vertebrate gut symbiont Lactobacillus reuteri PLoS Genet 7:e1001314 Su MSW, Oh PL, Walter J, Gänzle MG (2012) Phylogenetic, genetic, and physiological analysis of sourdough isolates of Lactobacillus reuteri: food fermenting strains are of intestinal origin Appl Environ Microbiol 78:6777–6780 Hammes WP, Hertel C (2006) The genera Lactobacillus and Carnobacterium Prokaryotes 4:320–403 10 Salovaara HO (2006) Cereal-based alternatives to dairy snacks of yogurt-type Paper presented at World Grain Summit: foods and beverages, San Francisco, 17–20 Sept 2006 http://www aaccnet.org/meetings/Documents/Pre2009Abstracts/2006Abstracts/S-68.htm 11 Groenewald WH, Van Reenen CA, Todorov SD, Du Troit M, Witthuhn RC, Holzapfel WH, Dicks LMT (2006) Identification of lactic acid bacteria from vinegar flies based on phenothpic and genotypic characteristics Am J Enol Vitic 57:519–525 12 Minervini F, Di Cagno R, Lattanzi A, De Angelis M, Antonielli L, Cardinali G, Cappelle S, Gobbetti M (2012) Lactic acid bacterium and yeast microbiotas of 19 sourdoughs used for traditional/typical Italian breads: interactions between ingredients and microbial species diversity Appl Environ Microbiol 78:1251–1264 13 Nout MJ (2009) Rich nutrition from the poorest- Cereal fermentations in Africa and Asia Food Microbiol 26:685–692 14 Vogelmann SA, Seitter M, Singer U, Brandt MJ, Hertel C (2009) Adaptability of lactic acid bacteria and yeast to sourdoughs prepared from cereals, pseudo-cereals and cassava and the use of competitive strains as starter cultures Int J Food Microbiol 130:205–212 15 Sekwati-Monang B, Gänzle MG (2011) Microbiological and chemical characterisation of ting, a sorghum-based sourdough product from Botswana Int J Food Microbiol 150:115–121 16 Keeratipibul S, Luangsakul N, Otsuka S, Hatano Y, Tanasupawat S (2010) Application of the Chinese Steamed bun starter dough (CSB-SD) in breadmaking J Food Sci 75:596–604 17 Liu M, Nauta A, Francke C, Siezen RJ (2008) Comparative genomics of enzymes in flavor-forming pathways from amino acids in lactic acid bacteria Appl Environ Microbiol 74:4590–4600 18 Vogel RF, Pavlovic M, Ehrmann MA, Wiezer A, Liesegang H, Offschanka S, Voget S, Angelov A, Böcker G, Liebl W (2011) Genomic analysis reveals Lactobacillus sanfranciscensis as stable element in traditional sourdoughs Microbiol Cell Fact 10(Suppl 1):S6 19 Gobbetti M, De Angelis M, Corsetti A, Di Cagno R (2005) Biochemistry and physiology of sourdough lactic acid bacteria Trends Food Sci Technol 16:57–69 20 De Angelis M, Damiano N, Rizzello CG, Cassone A, Di Cagno R, Gobbetti M (2009) Sourdough fermentation as a tool for the manufacture of low-glycemic index white wheat bread enriched in dietary fibre Eur Food Res Technol 229:593–601 21 Maioli M, Pes GM, Sanna M, Cherchi S, Dettori M, Manca E, Farris GA (2008) Sourdoughleavened bread improves postprandial glucose and insulin plasma levels in subjects with impaired glucose tolerance Acta Diabetologica 45:91–96 22 Di Cagno R, De Angelis M, Lavermicocca P, De Vincenzi M, Giovannini C, Faccia M, Gobbetti M (2002) Proteolysis by sourdough lactic acid bacteria: effects on wheat flour protein fractions and gliadin peptides involved in human cereal intolerance Appl Environ Microbiol 68:623–633 23 Rizzello CG, De Angelis M, Di Cagno R, Camarca A, Silano M, Losito I, De Vincenzi M, De Bari MD, Palmisano F, Maurano F, Gianfrani C, Gobbetti M (2007) Highly efficient gluten degradation by lactobacilli and fungal proteases during food processing: new perspectives for celiac disease Appl Environ Microbiol 73:4499–4507 12 Perspectives 285 24 Di Cagno R, Barbato M, Di Camillo C, Rizzello CG, De Angelis M, Giuliani G, De Vincenzi M, Gobbetti M, Cucchiara S (2010) Gluten-free sourdough wheat baked goods appear safe for young celiac patients: a pilot study J Ped Gastroent Nutr 51:777–783 25 Greco L, Gobbetti M, Auricchio R, Di Mase R, Landolfo F, Paparo F, Di Cagno R, De Angelis M, Rizzello CG, Cassone A, Terrone G, Timpone L, D’Aniello M, Maglio M, Troncone R, Auricchio S (2011) Safety for patients with celiac disease of baked goods made of wheat flour hydrolyzed during food processing Clin Gastroenterol Pathol 9:24–29 26 De Angelis M, Cassone A, Rizzello CG, Gagliardi F, Minervini F, Calasso M, Di Cagno R, Francavilla R, Gobbetti M (2010) Gluten-free pasta made of Triticum turgidum L var durum: mechanisms of epitopes hydrolysis by peptidases of sourdough lactobacilli Appl Environ Microbiol 75:508–518 27 Coda R, Rizzello CG, Pinto D, Gobbetti M (2012) Selected lactic acid bacteria synthesize antioxidant peptides during sourdough fermentation of cereal flours M Appl Environ Microbiol 4:1087–1096 28 Böcker G (2006) Grundsätze von Anlagen für Sauerteig In: Brandt MJ, Gänzle MG (eds) Handbuch Sauerteig, 6th edn Behr’s Verlag, Hamburg, pp 329–352 29 Brandt MJ (2007) Sourdough products for convenient use in baking Food Microbiol 24:161–164 30 Sanz-Penella JM, Laparra JM, Sanz Y, Haros M (2012) Assessment of iron bioavailability in whole wheat bread by addition of phytase-producing bifidobacteria J Agric Food Chem 60:3190–3195 31 Kariluoto S, Edelmann M, Herranen M, Lampi AM, Shmelev A, Salovaara H, Korhola M, Piironen V (2010) Production of folate by bacteria isolated from oat bran Int J Food Microbiol 143:41–47 32 Haruta S, Ueno S, Egawa I, Hashiguchi K, Fujii A, Nagano M, Ishii M, Igarashi Y (2006) Succession of bacterial and fungal communities during a traditional pot fermentation of rice vinegar assessed by PCR-mediated denaturing gradient gel electrophoresis Int J Food Microbiol 109:79–87 Index A Acidity, 165–166 ADI catabolism See Arginine deaminase (ADI) catabolism AFLP See Amplified fragment length polymorphism (AFLP) AFM See Atomic force microscopy (AFM) Altamura bread, 90–91 American system, 87 Amino acid metabolism ADI catabolism, 195, 196 cystathionine, 197–198 glutamine and glutamate, 195–197 peptides and free amino acids, 194–195 phenylalanine, 197 Amplified fragment length polymorphism (AFLP), 139 Antibacterial compounds bacteriocin formation, 204 prevention, bread spoilage, 204 reutericyclin, 205 Antifungal compounds, 203–204 Antimicrobial compounds, sourdough LAB antibacterial, 204–205 antifungal, 203–204 inhibitory activity, 202 leavened baked goods, 202 Arabinoxylans (AX) technological properties, 17 WEAX and WUAX, 219 xylanase enzymes, 235 Arginine deaminase (ADI) catabolism, 195, 196 Atomic force microscopy (AFM), 78 AX See Arabinoxylans (AX) B Bacteriocin formation, 204 Baked goods aroma and flavour compounds, 89 vs baker’s yeast, 281 and bread (see Bread) cereal, 15 classification, 47–48 degradation, cereal proteins, 194 description, 47 flavor compounds, 195 glutamate, 195 leavening agents (see Leavening, agents) making process (see Baking process) production, 94 quality, 97 quality assessment, dough, 73–79 salt, sugar and fats, 56–57 sourdough, water, 55–56 wheat flour, 194 Baker’s yeast production fermentation, 175–176 raw materials, 174–175 use, molasses, Saccharomyces cerevisiae, 57 Baking process aim and modifications, 58, 59 artisanal production, 72 colour intensity and vapour, 70 complex chemical reactions, 68, 70 continuous processes, 61 description, 68 discontinuous processes (see Straight-dough and sponge-and-dough method) M Gobbetti and M Gänzle (eds.), Handbook on Sourdough Biotechnology, DOI 10.1007/978-1-4614-5425-0, © Springer Science+Business Media New York 2013 287 288 Baking process (cont.) dough makeup operations, 67–68 GF flours, 252–253 heating causes and porous network, 68 industrial production, 73 leavening, 66–67 lipid effects, wheat flour, 36–38 mixing, 61–66 ovens, 70–71 polar lipids, 38 protein–sugar interactions, 70 and storage, bread area, 68, 69 temperature gradient and surface areas, 68 vitamins, 236 Basic local alignment and search tool (BLAST), 137 Beverages boza, 265–268 bushera, 271 chicha and kishk, 272 description, 265 hulu-mur, 275–276 kvass, 272–274 mahewu, 270–271 pozol, 271–272 sourish shchi, 274–275 togwa, 268–270 Biodiversity, microbial species diversity See Microbial species diversity BLAST See Basic local alignment and search tool (BLAST) Boza characteristics, 266 description, 265–266 enzyme activity, 268 fermentation, process, 266 glucose and free amino nitrogen, 266–267 LAB and yeast strains, 267 sensory and rheological properties, 268 Bread acidified and leavened, 7–8 Altamura, 90–91 baked goods, 13 and baked goods, 48 baker’s yeast, 86 black and white, brewer’s yeast, cereal, 28 dough strength and volume, 27 and flour, flour performance, 54–55 French, 5, 91–92 GF, 254–258 gliadins and glutenins, 49 Greece, Index large-scale, military, milling process (see Milling) oldest leavened and acidified, pain viennois, quality, 29, 233 recipe, rye and wheat sourdoughs, 30 rye sourdough, 92 San Francisco, 93–94 sourdough, 247–250 starch gel, 15 structure (see Bread structure) white pan, 92–93 Bread making baker’s yeast production, 174–176 biotechnology, novel types, sourdough, 99 brewer’s yeast, and cake production, 85 continuous processes, 61 discontinuous processes, 58–61 dough properties, 31 dry baker’s yeast, 177 fresh baker’s yeast, 177 glucans and fructans, 254 HMW-GS, 21 industries, 100 Parisian bakers, protocol, 88 rye-flour, 92, 99 techniques and knowledge, WEAX, 17 wheat, 29 yeast, Bread structure CO2 formation, 223 description, 217 enzymes, 220 EPS, 220–223 fermentations and synergistic affects, 225 gluten proteins, 217–218 organic acids, 218–219 rye flour, 218 Bushera, 271 C Carbohydrate metabolism EMP pathway, 185, 186 external acceptors, electrons acetate and ATP synthesis, 188 description, 186 fructose, 188 oxygen, 188 heterofermentative strains, 185 Index organic acids, 189–190 6-phosphogluconate/phosphoketolase (6-PG/PK) pathway, 185, 187 use, energy sources b-glucosidase activity, 191 L amylovorus DCE 471, 190 levansucrase, 190 maltose phosphorylase, 190–191 Carbohydrates NSP, 16–18 starch (see Starch) CBP See Chorleywood bread process (CBP) Cell-envelope-associated proteinase (CEP), 191, 192 Cell-to-cell communication, 206–207 CEP See Cell-envelope-associated proteinase (CEP) Cereal fermentation, LAB and yeast biopolymers, 230–235 EPS, 238–239 micronutrients, 235–238 Cereal food dietary fibre, 234 macro-and microstructure, 230 Cereal grains carbohydrates (see Carbohydrates) chemical composition, 12, 13 cool-season and rice, 11 description, 11 lipids (see Lipids) minerals, 38–39 production, 11, 12 proteins, 18–36 size and weight, 12 spring, 12 vitamins, 39 warm-season, 11 wheat, rye and barley, 11–12 Cereals See also Cereal grains bakers’ yeast and fermentation process, 129 beverages (see Beverages) biopolymers dietary fibre, 234–235 protein, 232–234 starch, 230–232 direct environment, 130 empirical techniques and fundamental measurements, 73 fermentation, LAB and yeast (see Cereal fermentation, LAB and yeast)flour types, 129 foods, GF products, 245–247 289 house microbiota and LAB species, 129 microbiological stability, 128 microorganisms, competitive yeast and LAB species, 128–129 phenolic compounds, 205 proteinases, 191 proteins, degradation, 194 raw, roasted/boiled, Chicha, 272 Chorleywood bread process (CBP), 60–61 CLSM See Confocal laser scanning microscopy (CLSM) Confocal laser scanning microscopy (CLSM), 78 Culture-dependent approaches LAB AFLP and ribotyping, 139 API system, 138 DNA fingerprinting methods, 139 housekeeping genes, 140 LGT, 141 MALDI-TOF MS, 138–139 MLSA and MLST, 141 MS methods, 138 PFGE, 139–140 protein profiling and SDS-PAGE, 138 RAPD-PCR, 139 sequence-based analysis, 140 single-locus sequence analysis, 140–141 yeasts BLAST and PCR, 137 DNA-based methods, 136 genetic regions and low sequence divergence, 136 LTR sequences, 138 phenotypic “characterization”, 136 S cerevisiae and Ty elements, 138 single-copy protein-coding gene sequences, 137 Culture-independent approaches community fingerprinting methods, 142 microarray technology, 142–143 PCR assays and probe-based methods, 141 real-time PCR technology, 141 Cystathionine metabolism, 197–198 D Dietary fibre arabinoxylans function, 235 bran sourdough, 234 cereal foods and sourdough fermentation, 234 290 Dietary fibre (cont.) description, 234 physiological effects and germ, 235 rye and wheat, 234 Differential scanning calorimetry (DSC), 15 Disulfide bonds cysteines Ca and Cb, 27 description, 24 2D structures, C-terminal domain, 24, 26 head-to-tail, 27 LMW-GS, 24, 27 Dough rheology fundamental measurements, 76–77 quality assessment baking properties, 74, 75 descriptive empirical measurements, 73–74 Dough inflation system, 76 Extensograph and Alveograph, 74 Farinograph and Mixograph, 74 Kieffer extensibility rig, 76 Mixolab, 74 rheofermentometer, 74 textural properties, 76 Dry baker’s yeast, 177 DSC See Differential scanning calorimetry (DSC) E Embden-Meyerhof-Parnas (EMP) pathway, 185, 186 EMP pathway See Embden-Meyerhof-Parnas (EMP) pathway Enzymes ADI, OTC and CK, 195 breads, 30 bread structure glutathione reductase, 220 proteolysis, 220 sourdough metabolites, 220, 221 cross-linking promoting, 247 dihydroxyacetone kinase (DAK1 and DAK2), 167 endogenous, 252 glycerol dehydrogenase (GCY1 and YPR1), 167 hexokinase, 190–191 hydrolases, 49 hydrolytic, 86–87 hydrolyzing, 34–35 inhibitors, 35–36 levansucrase, 190 Index oxidizing, 35 phosphoketolase, 191 proteolytic, 253 EPS See Exopolysaccharides (EPS) Exopolysaccharides (EPS) biosynthesis and HoPS structure, 198–200 classification, 220 description, 238 formation, 198 FOS and GOS, 254 glucan and fructan synthesis, 220–221 gluten-free baking, 223, 224 HoPS, 221–222, 254 IMO, 238 lactobacilli, 238–239 NDO and SCFA, 238 production and formation, HoPS, 200–202 strain collections, sourdough LAB, 198 sucrose metabolism, 222–223 Weissella strains, 255 F Fermentation acidity, 165 bacteriocin, 204 baker’s yeast production emulsifiers, 176 formulas, process, 175, 176 stock fermentation, 175 yeast mixture, 175 biogas/bioethanol, 11 boza, 265–268 bread dough, structure (see Bread structure) bushera and pozol, 271–272 and development, GF sourdough starters, 250–252 effect, parameters, 184 EPS, 198 GF sourdough, 248 grain, 4–5 heterolactic, 187 homofermentative metabolism, hexoses, 185 homolactic, 186 hulu-mur, 276 industrial and artisanal use, 282–283 kamut flour, amino acids, 158, 159 291 Index kishk, 272 kvass, 273–274 LAB and yeasts, 158–159 leavened loaf, bread, 31 leavening, 58–59 and leavening, lipid oxidation, 206 low temperature, 164, 165 mahewu, 270–271 microbial metabolism, 282 pentoses and hexoses, 191 pH-controlled, HoPS, 201 phenolic compounds, 205–206 polish, and proofing rooms, 67 protein degradation, 30 rye malt sourdoughs, 194 sourdough, 229, 257–258 and sourdough applications, 85–101 sourish shchi, 274–275 stages, proteolysis, 193 sterols, 169 temperature, 131 togwa, 268–270 yeast metabolism, 159–163 Flavor compounds, 189, 194–195 French bread (pain au levain), 5, 91–92 French system, 86–87 Fresh baker’s yeast, 177 G b-Glucans, 18 Glutamine and glutamate metabolism, 195–197 Gluten amylose network, 218 enzyme activity, 234 free bread, 233 free products (see Gluten-free (GF) products) and gliadins, 49 glutathione reductase, 220–221 gluten-free baking, 223, 224 native, 27 proteolysis, 220 quantitative analysis, 219 swelling and water uptake, 218 wheat (see Wheat gluten) Gluten-free (GF) products batters, bread and flour, 246 celiac disease, 245 description, 245–246 enzymatic process, 247 EPS, 254–255 fermentations and development dominant species, 251 ecological studies, 251–252 heterofermentative species, 250 Weissella spp., 251 health benefits, 257–258 HPMC, 246 non-toxic proteins, 246 protein hydrolysis, 247 proteolysis, 252–253 shelf life improvement, 256–257 starch hydrolysis, staling, 255–256 TGase, 247 Glutenin macropolymers (GMP), 27–28 GMP See Glutenin macropolymers (GMP) H History and social aspects of sourdough bread, Egyptians, fermentation and leavening, France back-slopping and bread-making techniques, bread making method, 3, cervoise, dehydrate, levain-chef, pain mollet, 3–4 poolish and pain viennois, 4–5 Saccharomyces cerevisiae, socio-cultural and socio-economic factors., travail sur levains and levain tout point, Germany acidified and leavened, 7–8 baker’s yeast, brewing and baking, chemical acidulants, 8–9 commercialization, dried, rye flour, Greece, Italy baker’s yeast, black and white bread, Cato the Elder, characteristic shape, knotted and dark red crust, “military bread”, PDO/PGI, renaissance, 6–7 292 Homopolysaccharides (HoPS) bread making, 254 glucansucrases and fructansucrases levansucrases, 201 maltose, 202 optimum pH, 201 oral streptococci, 200 stress resistance, 201 sucrose concentration, 201–202 structure and EPS biosynthesis dextran, mutan and glucans, 200 fructans, 200 gene clusters, 198–199 glucansucrases and fructansucrases, 199 sucrose hydrolysis, 199–200 HoPS See Homopolysaccharides (HoPS) Housekeeping genes, 140 HPMC See Hydroxyl-propril-methylcellulose (HPMC) Hulu-mur, 275–276 Hydroxyl-propril-methyl-cellulose (HPMC), 246 I Identification culture-dependent approaches, 136–141 culture-independent approaches, 141–143 dominant and sub-dominant microorganisms, 95 head-to-tail disulfide bond, 27 lactic acid bacteria and yeasts, 96–97 IMO See Isomalto-oligosaccharides (IMO) Isolation LAB, 134–135 sourdough yeasts, 133–134 Isomalto-oligosaccharides (IMO), 238 K Kishk, 272 Kvass baker’s yeast, 273 description, 272 filtration, 273–274 kvass-making techniques, 273 production, 274 L LAB See Lactic acid bacteria (LAB) Lactic acid bacteria (LAB) acidity, 165–166 Index boza fermentations, 266–267 bread structure, 220 cereal fermentation, 229–239 culture-dependent approaches, 136–141 culture-independent approaches, 141–143 definition, 8–9 diacetyl, 171 fermentation, amino acids, 158 inter-species signalling mechanism, 172–174 isolation, 134–135 kvass, 273–274 mahewu, 270 phenotypic and genetic analyses, 96–97 physiology and biochemistry (see Physiology and biochemistry, LAB) pozol, 271–272 taxonomy classification, 113–114 dextran-producing species, 117 fingerprinting methods, 117 heterofermentative pediococci, 117 heterogeneous group and homofermentative, 113 Lactobacillus, 116–117 molecular DNA, 116 species diversity, sourdough fermentation, 114–116 togwa, 268–269 yeasts, Lactobacillus description, 116 strain, 30 Lactobacillus plantarum anti-fungal strain, 256 fermentation processes, 129 isolated amylolytic strains, 255 isolation, 116 phenylalanine catabolism, 197 source tracking, 141 strains, 95 Lactobacillus sanfranciscensis (L sanfranciscensis) association, maltose-negative yeast species, 128 description, detection, 134 fermentation, 131 genome sequencing, 279 growth and metabolism, 158–159 laboratory-scale fermentation process, 132 metabolites, 171, 172 peptidase system, LAB, 191–193 phenylalanine catabolism, 197 Index starter strain, 251 wheat and/rye flour sourdoughs, 88 wheat sourdoughs, 128 Lateral gene transfer (LGT), 141 Leavening acidity, 165–166 agent, agents Baker’s yeast, 57 chemical, 57–58 extensographic analyses, 66 fermentation and proofing rooms, 67 microalveoli and danish pastry, 66 semi-solid mass and volume expansion, 66 viscoelastic properties and alveoli retained, 66 and fermentation, microbial, strains, 165 LGT See Lateral gene transfer (LGT) Lichenins, 18 Lipids composition nonstarch, 36, 37 phospho and glyco, 36, 37 starch, 36 effects, baking performance, 36–38 membranes (see Membrane lipids) metabolism, 206 polar, 57 polar, baking, 38 vitamins, 235 LMW See Low-molecular-weight (LMW) Lopez, H.W., 257 Low-molecular-weight (LMW), 16 M Mahewu, 270–271 MALDI-TOF See Matrix-assisted laser desorption/ionization-time-of-flight (MALDI-TOF) Matrix-assisted laser desorption/ionizationtime-of-flight (MALDI-TOF), 138–139 Membrane lipids homeoviscous adaptation, 167 SFAs and UFAs, 167 sterols, 169 temperature, fatty acid composition, 168–169 293 Metabolic proteins enzyme inhibitors, 35–36 hydrolyzing enzymes carbohydrate-degrading, 34 proteolytic, 34–35 oxidizing enzymes, 35 Microbial species diversity cereals and raw materials, 128–130 origin Altamura and Pugliese bread, 118 bread production and craftsmanship, 118 LAB species and rye bread baking, 118 leavening, 117 “sour”, 118 strains, 119 region-specific maltose metabolism, 128 maltose-positive LAB species, 128 nonexhaustive overview, LAB, 119–127 single isolations, yeast and LAB species, 128 technology aeration and LAB, 132 backslopping practices, 132 chemical composition and coarseness, 130 fermentation temperature, 131 growth, sourdough LAB, 131 pH value, 131–132 starter cultures, 130–131 type II/ industrial sourdoughs, 130 type III sourdoughs, 130 type I/traditional sourdoughs, 130 Micronutrients minerals, 236–237 phytochemicals, 237–238 vitamins, 235–236 Milling breaking system, 51 cereals, 39 chemical composition, wheat regions, 50 cleaning, 53–54 composition, flour extraction rate, 52–53 debranning and pearling, 54 description, 49 durum wheat, 52 external layers and germ, caryopsis, 52 “flour extraction yield”, 49–50, 52 grains and sieving, 18 kernel and wheat operations, 51 sieving/grading section, 51–52 sizing/purification system, 51 294 Milling (cont.) stages and flour classification, 50 starchy endosperm, 49 Minerals constituents, 38–39 micronutrients, 236–237 and phytochemical, 246 Mixing, baking process different times and speeds, 62 dough development, 62–63 “level of absorption”/“hydration”, 61 microscopic level, 62 mixers advantages, plant, 65–66 Artofex, 63 carousel system, 65 Chorleywood method, 63 classification, 63 high-speed and auxiliary equipment, 63 planetary and mixing tools, 64–65 physical characteristics, flour, dough and bread, 62 stiff and soft/slack doughs, 61 MLSA See Multilocus sequence analysis (MLSA) MLST See Multilocus sequence typing (MLST) Molecular weight distribution (MWD) GMP, 27–28 native gluten proteins, 27 native wheat storage (gluten) proteins, 27, 28 rye storage proteins, 28 Multilocus sequence analysis (MLSA), 141 Multilocus sequence typing (MLST), 141 MWD See Molecular weight distribution (MWD) N NDO See Non-digestible oligosaccharides (NDO) Near-infrared spectroscopy (NIR), 78–79 NIR See Near-infrared spectroscopy (NIR) NMR See Nuclear magnetic resonance (NMR) Non-digestible oligosaccharides (NDO), 238 Nonstarch polysaccharides (NSP) arabinoxylans (AX), 17 b-glucans, 18 nutritional point, 16 NSP See Nonstarch polysaccharides (NSP) Nuclear magnetic resonance (NMR), 79 Nutrition, 281–282 Index O Organic acids amylase activity, 219 citrate metabolism, 189 L parabuchneri, 190 malate and fumarate, 189 optimum pH, 218–219 quantitative analysis, 219 swelling and solubility, gluten proteins, 218 WEAX and WUAX, 219 Osborne, T.B., 18 Osmotic stress, 166–167 Ovens Ancient, 70 artisanal bakeries, 71, 72 characteristics, 70 cyclotherm, 70 “direct and indirect firing system”, 70 heat, 70–71 industrial bakeries and shutters control, 71 microwave and modern rack, 71 Oxidative gelation, 17 P Panettone cake, 93 Pentosans, 17 PFGE See Pulsed-field gel electrophoresis (PFGE) Phenolic compounds, 205–206 Phenotypic and genetic analyses, LAB and yeasts, 96–97 Phenotypic and genotypic analyses, 135 Phenylalanine metabolism, 197 Physico-chemical parameters acetic acid plays, 98 dough yield (DY), 97–98 endogenous and exogenous factors, sourdough characteristics and performances, 97, 98 fermentation quotient (FQ), 99 pH, 98 TTA, 98–99 Physiology and biochemistry, LAB amino acid metabolism, 194–198 antimicrobial compounds (see Antimicrobial compounds, sourdough LAB) carbohydrate metabolism, 185–191 cell-to-cell communication, 206–207 description, 183 EPS, 198–202 general growth and stress parameters, 184–185 295 Index lipid metabolism, 206 phenolic compounds, 205–206 proteolysis, 191–194 Physiology and biochemistry, sourdough yeasts bread-making, 174–177 carbohydrate metabolism (see Yeast metabolism) catabolic enzymes and permeases, 157–158 cereal dough, 156 cultivation methods, 155 description, 155 effect, process parameters, 158–159 fermentation, kamut flour, 158, 159 gene expression, 156 growth, Saccharomyces cerevisiae, 158 metabolites (see Yeast metabolites) NaCl and a-amylase supplementation, 156, 157 nitrogen metabolism and regulation, 156–157 quorum sensing, 171–174 stress response (see Stress response) yeast cells, 158 Phytochemicals, micronutrients, 237–238 Pliny the Elder, G., Pozol, 271–272 Proteins amino acid composition, flour, 18, 19 bioactive peptides, 233 cereal and wheat, 232 degradation, prolamin, 233 gluten and WSE, 233 LAB and baked cereal goods, 234 metabolic (see Metabolic proteins) Osborne fractions albumins and globulins, 19 cereal flour, 18–19 geno type, 20 prolamins, 19 quality, gluten-free bread, 233 storage (see Storage proteins) VSL#3 and proteolysis, 232 Proteolysis baking performances, GF flours, 252–253 bioactive peptides, 194 CEP, 191, 192 degradation, cereal proteins, 194 peptidases, L sanfranciscensis, 191–193 reducing toxicity, 253 stages, fermentation, 193 Pulsed-field gel electrophoresis (PFGE), 139–140 Q Quality assessment, dough image analysis, 77–78 microscopy, 78 rheology (see Dough rheology) spectroscopy, 78–79 Quorum sensing cell-free wheat flour hydrolyzed (WFH), 172, 173 cell-to-cell communication, 206 Histoplasma capsulatum, 171–172 inter-species signalling mechanism, 172–174 morphological transition, S cerevisiae, 172 R Reutericyclin, 205 Rye sourdough bread, 92 S San Francisco bread, 93–94 Saturated fatty acids (SFAs), 167 SCFA See Short-chain fatty acids (SCFA) SFAs See Saturated fatty acids (SFAs) Short-chain fatty acids (SCFA), 238 Sourdough vs active sourdoughs, 99–100 Altamura bread, 90–91 biological starter, 94 bran, 234 bread GF fermentations and properties, batters, 247, 248 LAB and yeasts, 247 microbiota, GF products, 247, 249–250 bread and baked good characteristics, 94 bread structure (see Bread structure) and cereal beverages(see Beverages) definition, 85–86 fermentation, 66–67, 229, 257–258 French bread (pain au levain), 91–92 history and social aspects of sourdough, 1–9 industrial and artisanal use, 282–283 leavening, 60 microbial ecology back-slopped sourdoughs, 279 genome sequencing, 279 sucrose and maltose, 280 wheat and rye, 280 nutrition, 281–282 panettone cake, 93 296 Sourdough (cont.) performance evaluation media cycloheximide, 96 microbiological and physico-chemical parameters, 95 phenotypic and genetic analyses, 96–97 physico-chemical parameters, 97–99 physiology and biochemistry, LAB, 183–207 physiology and biochemistry, sourdough yeasts, 155–177 preparation and storage (see Sourdough preparation and storage) product quality, 281 read vs straight dough bread, 236 rye, 17, 30 rye sourdough bread, 92 San Francisco bread, 93–94 shelf life improvement, 256–257 sponge dough, 90 vs stabilized sourdoughs, pure cultures, 100–101 starters, 250–252 strains, Lactobacillus plantarum, 95 type I, 88–89 type II and III, 89 wheat, rye/spelt, 94 white pan bread, 92–93 yeasts (see Sourdough yeasts) Sourdough and civilization See History and social aspects of sourdough Sourdough preparation and storage American system, 87 DY 225–250, 88 French system, 86–87 liquid, 88 Sourdough yeasts identification, 135–143 isolation, 133–134 taxonomy analyzed, yeast diversity, 107–111 basidiomycetous and genera, 106 C humilis/C milleri, 112–113 classification, 106 DNA-DNA, 112 HaeIII, 113 Hansenula and Pichia, 106 Saccharomyces and saccharomycetales, 106 species, ecosystem, 107, 112 vegetative growth, 105 Sourish shchi, 274–275 Starch amylose and amylopectin, 13–14 characteristics, 230 Index degradation prevention, description, 13 dietary carbohydrate and solid–liquid two phase reaction, 230 endosperm, 49 fermentation, wheat and rye flour matrix, 231 gelatinised and amylose-rich, 230 gelatinization, 218 GI and II, 230, 231, 232 granules, 14 hydrolysis, 255–256 interaction, lipids, 16 macro-and microstructure, cereal foods, 230 retrogradation, 218, 230–231 rye breads baked and wheat flour-based products, 231 structure, processing amylose molecules and staling endotherm, 16 DSC and mixing starch absorbs, 15 LMW and crystallization, 16 viscosity measurements and retrogradation processes, 15 water-protein, 79 Starter cultures boza fermentation, 268 production, 266, 267 CO2 formation, 223 dried grapes, food production, 280 Lb sanfranciscensis, 129 meat and dairy fermentations, 283 sourdoughs, 251–252 starch hydrolysis, 255 type II and III sourdoughs, 129–130 Storage proteins classification, 48 classification and primary structures amino acid sequences, 22 HMW group, 21–22 interchain disulfide bonds, 22 LMW group, 23–25 MMW group, 22 PAGE, 21 partial amino acid sequences, domain B of HMW-GS, 22, 23 quantitative composition, 23, 26 wheat, rye, barley and oats, 20–21 corn, millet, sorghum and rice, 33 disulfide bonds, 24–27 enzymes, 30 fertilization, 28–29 germination and infections, 29 297 Index heat and high pressure, 30 MWD, 27–28 oxidation, 29–30 wheat gluten, 30–33 Straight-dough and sponge-and-dough method baker’s yeast, 60 CBP, 60–61 characteristics, 58, 59 fermentation, 58 ingredients, 60 physical characteristics, flour, dough and bread, 60, 62 polish, poolish/viennese methods, 60 Stress response acidity, 165–166 environmental, 128 gene expression program, 163 low temperature, 164–165 membrane lipids (see Membrane lipids) osmotic stress, 166–167 process parameters, 163 transcription factor, Msn2, 163 yeast responses and growth rate, 163–164 T Taxonomy LAB, 113–117 sourdough yeasts, 105–113 TEM See Transmission electron microscopy (TEM) Togwa dominant microbes, 269, 270 folate production, 269–270 germinated sorghum, 268 LAB and yeasts, 268–269 manufacturing process, 268, 269 proteolytic activity, 270 yeast strains, 269 Tradition biotechnology, breads represent temporary, 7–8 cereal flour proteins, 18 culture, GF sourdoughs and products, 249–250 Italian sourdough bread, 90–91 mixing, 62–63 San Francisco bread, 93–94 sourdoughs, 88–89, 130 values, Traditional use of sourdough, 282–283 Transmission electron microscopy (TEM), 78 TTA, 98–99 U UFAs See Unsaturated fatty acids (UFAs) Unsaturated fatty acids (UFAs), 167, 169 V Vitamins constituents, 39 micronutrients, 235–236 and soluble sugars, 52 W Water extractable (WEAX), 219 Water unextractable arabinoxylans (WUAX), 219 WEAX See Water extractable (WEAX) Wheat flour barley and honey, Egyptians, glycolipids, 37 nonstarch lipids, 36 pH, 184 polar lipids, 37–38 “specific baking activity”, 37 toxicity reducing, 253 Wheat gluten cereals, 30 chemical bonds disulfide linkages, 31 covalent and noncovalent bonds, 32 cysteine and sodium metabisulfite, 31 dityrosine and isopeptide bonds, 31 dough retains, 30–31 hydrated monomeric and oligomeric proteins, 31 hydrophobic bonds, 32 interchain disulfide structure, 2D model, 32, 33 oxygen and S-S linkages, 31 “plasticizer”/“solvent”, 31 SH-SS interchange reactions, 31 WUAX See Water unextractable arabinoxylans (WUAX) Y Yeast baker’s, 5, 7, 8, 57 brewer’s, 3–5 cereal fermentation, 229–239 CO2 formation, 223 glucose, 222 lactic acid bacteria, 96–97 microscopic observations, 298 Yeast (cont.) physiology and biochemistry (see Physiology and biochemistry, sourdough yeasts) Yeast metabolism alcoholic fermentation, 160 carbon and energy sources, 159–160 glycolytic pathway, glycerol production, 160–161 hexose phosphate pathway, 162–163 hydrogen (electrons), 159 Index Pasteur, Kluyver, Custers and Crabtree effects, 161–162 respiration and fermentation, S cerevisiae, 162 Yeast metabolites amino acids, Ehrlich pathway, 169, 170 ethanol, methylpropanol, 2-and 3-methylbutanol, 171 “fermented taste”, 169 fusel alcohols, 169, 171 L sanfranciscensis and S cerevisiae, 171, 172